Methods and apparatus to use vibration data to determine a condition of a process control device

ABSTRACT

Methods and apparatus to use vibration data to determine a condition of a process control device are disclosed. An example method includes collecting first vibration data from a first sensor operatively coupled to a process control device during a calibration. The example method further includes calculating an operating threshold of the process control device based on the first vibration data, and determining a condition of the process control device if second vibration data associated with the process control device collected after the calibration exceeds the operating threshold.

FIELD OF THE DISCLOSURE

This disclosure relates generally to process control devices and, moreparticularly, to methods and apparatus to use vibration data todetermine a condition of a process control device.

BACKGROUND

Process control systems generally use a variety of process controldevices to control a process. Vibrations in components in these processcontrol devices are inherent during operation. Over time, componentsincluded in these process control devices are subject to stresses thatcause changes in vibration patterns associated with the components.These stresses may decrease performance of the process control devicesand reduce the remaining useful life of the components and, thus, theprocess control devices. As these stresses can impact a process controldevice to varying degrees, the useful life of a process control devicealso varies.

SUMMARY

An example method includes collecting first vibration data from a firstsensor operatively coupled to a process control device during acalibration. The example method further includes calculating anoperating threshold of the process control device based on the firstvibration data, and determining a condition of the process controldevice if second vibration data associated with the process controldevice collected after the calibration exceeds the operating threshold.

Another example method includes collecting first vibration data from afirst sensor operatively coupled to a process control device and secondvibration data from a second sensor operatively coupled to a pipecoupled to the process control device. The example method furtherincludes calculating a ratio based on the first vibration data and thesecond vibration data, and indicating a condition of the process controldevice if the ratio is greater than a threshold value.

Another example method includes collecting vibration data from a firstsensor operatively coupled to a process control device. The examplemethod further includes receiving diagnostic vibration data associatedwith the process control device. The example method further includescomparing the vibration data to the diagnostic vibration data, andindicating a condition of the process control device based on thecomparison.

Another example method includes collecting first vibration data from afirst sensor operatively coupled to a process control device. Theexample method further includes identifying a characteristic of theprocess control device from the first vibration data. The example methodfurther includes determining if the characteristic is within a knownrange, and when the characteristic is within the known range, indicatinga condition of the process control device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example process control system within which theteachings of this disclosure may be implemented.

FIG. 2 illustrates an example process control device that may be used toimplement example methods disclosed herein.

FIG. 3 illustrates an alternate example of the stem connector of FIG. 2.

FIG. 4 is a flow chart representative of an example method disclosedherein.

FIG. 5 is a flow chart representative of another example methoddisclosed herein.

FIG. 6 is a flow chart representative of another example methoddisclosed herein.

FIG. 7 is a flow chart representative of another example methoddisclosed herein.

DETAILED DESCRIPTION

Certain examples are shown in the above-identified figures and describedin detail below. In describing these examples, like or identicalreference numbers are used to identify the same or similar elements. Thefigures are not necessarily to scale and certain features and certainviews of the figures may be shown exaggerated in scale or in schematicfor clarity and/or conciseness. Additionally, several examples have beendescribed throughout this specification. Any features from any examplemay be included with, a replacement for, or otherwise combined withother features from other examples.

While the following methods and apparatus are described in conjunctionwith a control valve assembly, the example methods and apparatus mayalso be used with any other process control device. Processes such as,for example, industrial processes are usually controlled by a variety ofprocess control devices. These process control devices may includeactuators and linear valves. Over time, structural damage or wear to oneor more of the process control devices may develop and lead toconditions such as, for example, control instability and/or otherperformance degradation of the process control devices.

The examples described herein relate to processing vibration datacollected from a process control device and determining a condition ofthe process control device based on the vibration data. Vibration datamay have characteristics relating to frequency, acceleration,displacement and/or velocity associated with components of the processcontrol device and can provide information regarding the structural orfunctional integrity of the process control device. Vibration datanearing a threshold or a shift identified in the vibration data mayindicate the onset of a failure for which an alert may be provided to auser or other person. For example, vibration data can indicate controlinstability due to control system tuning, valve controller tuning,and/or other process issues relating to the process control device.

In some examples, vibration data collected from one or more vibrationsensors operatively coupled to a process control device can be processedto identify a threshold associated with a condition of the processcontrol device. For example, vibration data collected from a sensor,such as an accelerometer, operatively coupled to a component of theprocess control device can be collected during calibration and used tocalculate an operating threshold of the process control device.Alternatively, the operating threshold may be a known threshold such as,for example, an industry standard or accepted limit or threshold.Vibration data collected from the sensor after calibration can becompared to the operating threshold and a condition of the processcontrol device may be determined if the operating threshold is exceeded.

In other examples, vibration data is collected from an additional sensoroperatively coupled to a pipe, which is coupled to the process controldevice. In such examples, vibration data collected from a sensoroperatively coupled to the process control device and vibration datacollected from the sensor operatively coupled to the pipe may be used tocalculate a ratio. This ratio may be compared to a threshold value and acondition of the process control device may be determined when the ratioexceeds the threshold value. The value of the threshold may depend onthe location of the sensor operatively coupled to the process controldevice.

In other examples, diagnostic vibration data may be used to determine acondition of the process control device. Diagnostic vibration data mayinclude an operating threshold, a predetermined threshold, a thresholdvalue and/or a range. When the diagnostic vibration data includes afrequency range, a determination of the condition of the process controldevice may be made based on a comparison of the collected vibration datafrom a sensor operatively coupled to the process control device to thediagnostic vibration data.

FIG. 1 illustrates an example process control system 100 that may beused to implement the example methods and apparatus disclosed herein. Inthe illustrated example of FIG. 1, a process control device 102, avibration monitoring circuit 104, a controller 106 and a user interface108 may communicate via, for example, wired or wireless links. Inparticular, the example process control device 102 and the examplecontroller 106 of FIG. 1 may communicate via a data bus (e.g.,FOUNDATION Fieldbus™, HART™, Profibus™, Modbus™, Devicenet™, etc.) or aLocal Area Network (LAN).

The vibration monitoring circuit 104 of FIG. 1 collects the vibrationdata communicated by the process control device 102 and generates alertmessages to output to the controller 106. The example vibrationmonitoring circuit 104 of FIG. 1 and/or the example controller 106 ofFIG. 1 may be a digital valve positioner (DVP), a processor for datacollection and/or discrimination, and/or an asset management softwarepackage. Alternatively, the example vibration monitoring circuit 104 ofFIG. 1 and the controller 106 may be combined and/or integrated into,for example, a DeltaV™ controller.

The example controller 106 generates notifications, alert messages,and/or other information based on information received and/or collectedfrom the process control device 102 and/or the vibration monitoringcircuit 104. The example controller 106 of FIG. 1 also transmitsinformation (e.g., instructions) to the process control device 102and/or outputs information (e.g., alert messages) to the user interface108.

The example process control device 102 of FIG. 1 may be any number ofinput devices and/or output devices. In some examples, the input devicesinclude valves, pumps, fans, heaters, coolers, mixers, and/or otherdevices, and the output devices include accelerometers, thermometers,pressure gauges, concentration gauges, fluid level meters, flow meters,vapor sensors, valve positioners, and/or other devices.

The example user interface 108 of FIG. 1 is any device that processesinputs and outputs such as, for example, a computer, a workstation, aserver, and/or a mobile device, etc. User input may be communicated tothe user interface 108 by the input device 110 such as, for example, akeyboard, a stylus pen, a mouse, and/or a touch screen, etc. Output fromthe user interface 108 may be communicated to the user by the outputdevice 112 such as, for example, a monitor (e.g., displaying an alertmessage) and/or speaker (e.g., emitting an audible alert), etc.

Although a single example vibration monitoring system 104 and examplecontroller 106 are shown in FIG. 1, one or more additional examplevibration monitoring circuits 104 and/or controllers 106 may be includedin the example process control system 100 of FIG. 1 without departingfrom the teachings of this disclosure.

FIG. 2 illustrates an example process control device 200 that may beused to implement the example methods and apparatus disclosed herein.The example process control device 200 shown in FIG. 2 is a linearvalve. However, other process control devices may also be used toimplement the example methods and apparatus disclosed herein. Theexample process control device 200 includes an actuator 204, an actuatorrod 206, a stem connector 208, a valve stem 210, a valve body 212, and avalve plug 214. The example valve body 212 of FIG. 2 may also be coupledto an upstream pipe 216 and a downstream pipe 218. First through fifthsensors 220, 222, 224, 226 and 228 are coupled to the example actuator204, the example actuator rod 206, the example stem connector 208, theexample valve stem 210 and the example upstream pipe 216, respectively.In the example of FIG. 2, the sensors 220-228 may include one or moreaccelerometers and/or other vibration or motion sensors. Although notshown, one or more sensors may also be coupled to the downstream pipe218. Additionally, although the example process control device 200includes the sensors 220-228, it is possible to use fewer sensors oradditional sensors in the locations shown in FIG. 2 or in one or moredifferent locations.

The mechanical connections between the components of the example processcontrol device 200 may vibrate during operation of the process controldevice 200. These vibrations may be due to a variety of sources such asmotor or actuator operation, fluid movement through the process controldevice 200, looseness of one or more mechanical connections, etc. Insome examples, vibrations or vibration patterns may indicate aparticular condition of the process control device 200. For example,vibration data retrieved from a sensor coupled to the actuator rod 206(e.g., the actuator rod sensor 222), the stem connector 208 (e.g., thestem connector sensor 224) or the valve stem 210 (e.g., the valve stemsensor 226) may indicate looseness, wear or other degradation of thecorresponding component.

In the illustrated example of FIG. 2, vibration data collected via oneor more of the sensors 220-228 is communicated (e.g., via a wired orwireless link) to the example vibration monitoring circuit 104. Forexample, vibration data corresponding to the example actuator 204 ismeasured or gathered by the actuator housing sensor 220. This vibrationdata may be communicated from the actuator housing sensor 220 to theexample vibration monitoring circuit 104 for further processing.

The vibration data received from the example sensors 220-228 may be usedby the example vibration monitoring circuit 104 to indicate a conditionof the process control device 200. The vibration monitoring circuit 104determines the characteristics of the vibration data relating tofrequency, acceleration, displacement and/or velocity collected from thesensor(s) 220-228 coupled to the corresponding component(s) of theprocess control device 200. In some examples, the vibration monitoringcircuit 104 also identifies the source of the vibration data (e.g., thesensor from which the data is obtained). In some examples, the vibrationmonitoring circuit 104 identifies the axis of movement associated withthe vibration data. For example, the vibration data received from asensor may correspond to displacement of a component of the processcontrol device 200 along a horizontal axis and/or a vertical axis.

The example vibration monitoring circuit 104 compares the identifiedcharacteristic(s) of the vibration data to a known threshold value(s)and/or range(s). For example, displacement, velocity and/or accelerationcharacteristic(s) of the vibration data may be compared to a knownthreshold value or multiple threshold values. When the vibration dataexceeds the known threshold value(s), the example vibration monitoringcircuit 104 may identify a condition of the process control device 200such as a loose bonnet fastener 230. Additionally or alternatively, thefrequency characteristics of the vibration data may be compared to athreshold value and/or to a range or multiple ranges. For example, abroken or damaged valve plug 214 may be identified by the examplevibration monitoring circuit 104 when a fundamental frequency ofvibration exceeds 100 Hertz (Hz). Additionally or alternatively, theexample vibration monitoring circuit 104 may identify, for example,control instability in the example process control device 200 due tocontrol system tuning or valve controller tuning when a fundamentalfrequency of vibration is between 1 Hz and 10 Hz.

The known threshold values and/or ranges used by the example vibrationmonitoring circuit 104 to compare to the vibration data may be stored ina local memory in the example vibration monitoring circuit 104 and/orretrieved from a remote storage via a wired or wireless link. The knownthreshold value(s) and/or range(s) may be based on information gatheredduring product testing in a laboratory or may be set by industrystandards. For example, laboratory testing may identify vibration datacharacteristic(s) associated with a component of the process controldevice 200 corresponding to particular conditions of the process controldevice 200. Additionally or alternatively, the example vibrationmonitoring circuit 104 may calibrate during, for example, an initialsetup period. During calibration, the example vibration monitoringcircuit 104 may collect vibration data from the example sensors 220-228over a period of time (e.g., ten minutes) and normalize the vibrationdata. This normalized vibration data may be stored (e.g., in a localmemory) and may be compared to subsequently received vibration data bythe vibration monitoring circuit 104 to identify a condition of theprocess control device 200.

In some examples, the vibration monitoring circuit 104 compares thevibration data received from, for example, the example stem connectorsensor 224 to a threshold value corresponding to a condition relating tothe stem connector 208. For example, when the vibration data collectedfrom the stem connector sensor 224 (e.g., characteristics relating tofrequency) exceeds a threshold value, the vibration monitoring circuit104 may identify a condition associated with compromise of thestructural and/or functional integrity of the process control device200. For example, vibration data received from the stem connector sensor224 greater than 100 Hz may indicate internal damage to the valve body212 such as a broken valve plug 214 or piston ring in a piston actuator(not shown).

In some examples, the vibration monitoring circuit 104 compares thereceived vibration data to stored ranges corresponding to conditionsrelating to the process control device 200. For example, when thefrequency (e.g., fundamental) of the vibration data received from, forexample, the actuator rod sensor 222 is between 10 Hertz and 100 Hertz,the vibration monitoring circuit 104 may identify a condition associatedwith, for example, looseness of a component due to impaired guiding ofthe reciprocating parts due to a worn actuator guiding bushing 232.

In other examples, the vibration monitoring circuit 104 may calibrateprior to using vibration data collected from the sensors 220-228 toidentify a condition of the process control device 200. For example,when the process control device 200 is installed in a process controlsystem such as the example process control system 100 of FIG. 1, thevibration monitoring circuit 104 collects vibration data from a sensor(e.g., the example sensors 220-228) operatively coupled to a componentof the process control device 200 over a period of time. For example,the vibration monitoring circuit 104 may collect vibration data from theexample stem connector sensor 224 of FIG. 2 over a 24 hour period. Thecollected vibration data may then be normalized and a vibration pattern(e.g., natural frequency) of the example stem connector 208 duringoperation (e.g., an operating threshold and/or range) may be identifiedby the example vibration monitoring circuit 104. For example, the normaldistribution of the received vibration data is calculated.

Once calibrated, the vibration monitoring circuit 104 monitors thevibration data received from the example stem connector sensor 224. Whenthe vibration data received by the vibration monitoring circuit 104deviates from the normalized vibration pattern determined duringcalibration (e.g., the operating threshold and/or range), the examplevibration monitoring circuit 104 identifies a condition of the processcontrol device 200 such as a loose stem connector 208.

In other examples, the vibration monitoring circuit 104 continuously(e.g., periodically, aperiodically) collects vibration data from theexample stem connector sensor 224 and identifies a new vibration patternof the stem connector 208. When the new vibration pattern differs fromthe normalized vibration pattern (e.g., the natural frequency of thestem connector 208 during operation), the example vibration monitoringcircuit 104 may identify, for example, looseness in the movingcomponents of the valve assembly due to wear or damage to a sealassociated with the example valve plug 214.

In some examples, the vibration monitoring circuit 104 collects andprocesses vibration data from sensors coupled to multiple components ofthe process control device 200. For example, the vibration monitoringcircuit 104 collects vibration data from the trim (e.g., an internalcomponent in the process control device 200 such as the example actuator204) and from the external body (e.g., the example pipe 216) via theexample sensors 220 and 228, respectively. The example vibrationmonitoring circuit 104 may calculate a transmissibility ratio based onthe vibration data collected via the example sensors 220 and 228. Thetransmissibility ratio is a ratio of the output amplitude to the inputamplitude. Thus, in the illustrated example, this ratio represents anamplification of the movement from the pipe 216 to the actuator 204. Forexample, the transmissibility ratio may be calculated by the amount ofdisplacement measured by the actuator sensor 220 divided by the amountof displacement measured by the piping sensor 228. This ratio may becompared to a threshold and, when the ratio exceeds the threshold, thevibration monitoring circuit 104 may identify an excessive amount ofamplification as the center of gravity of the actuator 204 moves furtherfrom the pipe 216 centerline. Alternatively, the example vibrationmonitoring circuit 104 may calculate the difference between vibrationdata collected from the trim and the external body of the processcontrol device 200. For example, the vibration monitoring circuit 104may calculate the difference between frequencies collected from theexample sensors 220 and 228. When this difference exceeds a threshold,the vibration monitoring circuit 104 may identify instable tuning (e.g.,looseness in the guiding) due to a worn seal or excess vibration inducedby the process flow.

In the illustrated example of FIG. 2, when the vibration monitoringcircuit 104 identifies a condition of the process control device 200,the vibration monitoring circuit 104 outputs an indication to theexample controller 106 of FIG. 1 and/or the example user interface 108of FIG. 1. For example, when the vibration monitoring circuit 104identifies structural damage in the process control device 200, thevibration monitoring circuit 104 outputs an indication to the examplecontroller 106. In some examples, the vibration monitoring circuit 104outputs an indication to the example controller 106 when an event occurs(e.g., a condition is identified). In some examples, the vibrationmonitoring circuit 104 continuously outputs (e.g., periodically,aperiodically) an indication relating to the condition of the processcontrol device 200.

In some examples, a digital valve positioner (DVP) may also be coupledto the process control device 200 to collect information from theprocess control device. For example, the DVP may collect and determineinformation such as, for example, a position of the actuator rod 206and/or the valve stem 210, a direction of travel, information receivedfrom sensors (e.g., vibration data), and/or other information. Duringoperation, the DVP transmits the information to the controller 106 ofFIG. 1 and receives information from the example controller 106.

FIG. 3 illustrates an alternate example stem connector 302 that may beused with the example process control device 200 of FIG. 2. The examplestem connector 302 of FIG. 3 is coupled to the example actuator rod 206and the example valve stem 210 described above in connection with FIG.2. First through third sensors 304, 306 and 308 are operatively coupledto the example stem connector 208. Each of these sensors 304-308measures vibration data from the stem connector 302 on a mutuallyperpendicular axis. For example, the first sensor 304 measures vibrationdata relating to the example stem connector 302 (e.g., displacement ofthe stem connector 302) along a first axis relative to the stemconnector 302, the second sensor 306 measures vibration data relating tothe example stem connector 302 (e.g., displacement of the stem connector302) along a second axis relative to the stem connector 302, and thethird sensor 308 measures vibration data relating to the example stemconnector 302 (e.g., displacement of the stem connector 302) along athird axis relative to the stem connector 302.

In the illustrated example of FIG. 3, the example vibration monitoringcircuit 104 collects vibration data from each sensor coupled to theexample stem connector 302 (e.g., the sensors 304-308), processes thevibration data and compares the vibration data to a known thresholdand/or range. For example, the vibration monitoring circuit 104calculates a ratio based on the received vibration data from first andsecond sensors 304 and 306. In the illustrated example, when thecalculated ratio exceeds a threshold associated with vibration data fromthe stem connector 302, the vibration monitoring circuit 104 identifiesa condition of the process control device 200 of FIG. 2.

FIGS. 4, 5 and 6 are flowcharts representative of example methodsdisclosed herein. Some or all of the example methods of FIGS. 4, 5 and 6may be carried out by a processor, the controller 106 and/or any othersuitable processing device. In some examples, some or all of the examplemethods of FIGS. 4, 5 and 6 are embodied in coded instructions stored ona tangible machine accessible or readable medium such as a flash memory,a ROM and/or random-access memory RAM associated with a processor.Alternatively, some or all of the example methods of FIGS. 4, 5 and 6may be implemented using any combination(s) of application specificintegrated circuit(s) (ASIC(s)), programmable logic devices(s) (PLD(s)),field programmable logic device(s) (FPLD(s)), discrete logic, hardware,firmware, etc. Also, one or more of the operations depicted in FIGS. 4,5 and 6 may be implemented manually or as any combination of any of theforegoing techniques, for example, any combination of firmware,software, discrete logic and/or hardware. Further, although the examplemethods are described in reference to the flowcharts illustrated inFIGS. 4, 5 and 6, many other methods of implementing the example methodsmay be employed. For example, the order of execution of the blocks maybe changed, and/or some of the blocks described may be changed,eliminated, sub-divided, or combined. Additionally, any or all of theexample methods of FIGS. 4, 5 and 6 may be carried out sequentiallyand/or carried out in parallel by, for example, separate processingthreads, processors, devices, discrete logic, circuits, etc.

With reference to FIGS. 1-3, the example method or process 400 of FIG. 4begins by collecting vibration data associated with a component of theprocess control device 200 (block 405). In some examples, the mechanicalconnections between the components of the process control device 200 mayintroduce vibrations during operation of the process control device 200.During operation, the sensor operatively coupled to a component of theprocess control device 200 (e.g., the example sensors 220-228 of FIG. 2)measures the vibrations corresponding to the component. This vibrationdata is communicated (e.g., via a wired or wireless link) to the examplevibration monitoring circuit 104. The example vibration monitoringcircuit 104 continuously (e.g., periodically, aperiodically) collectsthe vibration data (e.g., communicated from the sensors 220-228)corresponding to the component of the process control device 200.

At block 410, the received or collected vibration data is compared to aknown threshold associated with the component of the process controldevice 200. In some examples, the vibration monitoring circuit 104identifies the sensor from which the vibration data was received and thecharacteristic(s) of the vibration data (e.g., frequency, displacement,acceleration and/or velocity). The vibration monitoring circuit 104compares the vibration data or characteristic(s) with the knownthreshold corresponding to the received vibration data. In someexamples, the known threshold is retrieved from a local memory in thevibration monitoring circuit 104. In other examples, the vibrationmonitoring circuit 104 retrieves the known threshold from a remotestorage. For example, the known threshold may be retrieved from thecontroller 106 or from a central facility via a data bus.

If the vibration data exceeds the known threshold, an alert message issent (block 415). For example, the vibration monitoring circuit 104and/or controller 106 generates and sends the alert message to the userinterface 108, which displays the alert message via the output device112. If the received vibration data does not exceed the known threshold,then the example method returns to block 405. Otherwise, the processends.

In some examples, the vibration monitoring circuit 104 compares thevibration data or characteristic(s) of the vibration data with multiplethresholds. For example, vibration data exceeding a first threshold butless than a second threshold may indicate a loose mechanical connection(e.g., due to a broken piston ring on the valve plug 214) and vibrationdata exceeding the second threshold may indicate a damaged component(e.g., a broken actuator spring 234).

FIG. 5 is a flowchart representative of another example process ormethod 500 disclosed herein. The example process or method 500 begins bycalculating a normalized vibration pattern associated with a processcontrol device 200 component (block 505). For example, the vibrationmonitoring circuit 104 may process the vibration data and calculate anormalized vibration pattern based on the vibration data. Thisnormalized vibration pattern represents an operating threshold or range(e.g., a natural frequency range) associated with the process controldevice 200 component during operation (e.g., during safe operation).

At block 510, the example vibration monitoring circuit 104 monitorsvibration data subsequently collected from the sensor operativelycoupled to the process control device 200 component (e.g., aftercalibration). In some examples, the vibration monitoring circuit 104continuously (e.g., periodically, aperiodically, etc.) collectsvibration data associated with the process control device 200.

At block 515, the example vibration monitoring circuit 104 or theexample controller 106 determines whether the vibration data deviatesfrom the normalized vibration pattern. For example, the vibrationmonitoring circuit 104 determines whether the vibration data fallsoutside of the operating range. If the vibration data falls outside ofthe operating range, an alert message is sent (block 520). If thevibration data is within the operating range, then the example methodreturns to block 510. Otherwise, the process ends.

In some examples, the vibration monitoring circuit 104 calibratesperiodically (e.g., recalibrates). For example, the vibration monitoringcircuit 104 calculates a normalized vibration pattern associated withthe process control device 200 component every 24 hours. In some suchexamples, when the vibration data is within the operating range (e.g.,no alert message was sent), the example method or process 500 includes acheck to see whether recalibration should be initiated. For example, thevibration monitoring circuit 104 checks whether a timer has expired. Ifrecalibration should be initiated, the example method returns to block505 rather than block 510.

In other examples, the vibration monitoring circuit 104 recalibratesaperiodically. For example, the method or process 500 returns to block505 when an alert message is sent.

FIG. 6 is a flowchart representative of another example process ormethod 600 disclosed herein. The example process or method 600 begins bycollecting vibration data associated with a component of the processcontrol device 200 and vibration data from a sensor operatively coupledto a pipe (e.g., the example upstream pipe 216 or the example downstreampipe 218 of FIG. 2), which is coupled to the process control device 200(block 605). For example, the vibration monitoring circuit 104 collectsvibration data from the actuator housing sensor 220 and the pipingsensor 228. The example vibration monitoring circuit 104 calculates atransmissibility ratio based on the vibration data collected from theactuator housing sensor 220 and the piping sensor 228 (block 610). Thistransmissibility ratio compares the vibration data associated with theactuator (e.g., the displacement characteristic of the vibration data)relative to the vibration data associated with the pipe (e.g., thedisplacement characteristic of the vibration data).

At block 615, the example vibration monitoring circuit 104 or thecontroller 106 determines whether the transmissibility ratio exceeds athreshold. If the transmissibility ratio exceeds the threshold, an alertmessage is sent (block 620). If the transmissibility ratio does notexceed the threshold, then the example method returns to block 605.Otherwise, the process ends.

FIG. 7 is a flowchart representative of another example process ormethod 700 disclosed herein. The example process or method 700 begins bycollecting usage information regarding the process control device 200(block 705). For example, the vibration monitoring circuit 104communicates with a digital valve positioner (DVP) and receivesinformation regarding, for example, operational cycles or distancetraveled. The example vibration monitoring circuit 104 updates thethreshold value(s) and/or range(s) based on the usage information (block710). For example, during each operation cycle, the seal associated withthe example valve plug 214 is subjected to a load and, thus, a stress.As a result, a portion of useful life is consumed. The example vibrationmonitoring circuit 104 adjusts (e.g., updates) the threshold value(s)and/or range(s) based on this reduced useful life information. Thethreshold value(s) and/or range(s) may be adjusted based on empirical orexperimental data stored in a local memory in the example vibrationmonitoring circuit 104. Thus, the vibration monitoring circuit 104adjusts the threshold value(s) and/or range(s) to reflect expectedchanges due to anticipated wear or damage through normal operation(e.g., distance traveled by the valve stem 210 during an operationalcycle).

At block 715, the example vibration monitoring circuit 104 collectsvibration data associated with a component of the process control device200. At block 720, the collected vibration data is compared to theupdated threshold value(s) and/or range(s) associated with the componentof the process control device 200.

At block 725, the example vibration monitoring circuit 104 or theexample controller 106 determines whether the vibration data exceeds theupdated threshold value(s) and/or range(s). If the vibration dataexceeds (or deviates from) the updated threshold(s), an alert message issent (block 730). If the vibration data does not exceed (or deviatefrom) the updated threshold(s), then the example method returns to block705. Otherwise, the process ends.

Although certain example methods, apparatus and articles of manufacturehave been described herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

What is claimed is:
 1. A method comprising: collecting, via a firstsensor operatively coupled to a process control device, first vibrationdata associated with the process control device during calibration ofthe process control device; calculating, by executing an instructionwith a vibration monitoring circuit, an operating threshold of theprocess control device based on the first vibration data; collectingusage information associated with the process control device, the usageinformation indicative of a remaining portion of useful life associatedwith the process control device; adjusting, by executing an instructionwith the vibration monitoring circuit, the operating threshold based onthe usage information, the adjusted operating threshold reflective ofthe remaining portion of useful life associated with the process controldevice; and determining, by executing an instruction with the vibrationmonitoring circuit, a condition of the process control device if secondvibration data associated with the process control device collectedafter the calibration exceeds the adjusted operating threshold.
 2. Amethod as defined in claim 1, wherein the first and second vibrationdata include acceleration data, velocity data, displacement data orfrequency data.
 3. A method as defined in claim 1, further comprising:collecting third vibration data from a second sensor operatively coupledto a pipe, the pipe coupled to the process control device; calculating aratio based on the second vibration data and the third vibration data;and determining the condition of the process control device when theratio exceeds a first threshold value.
 4. A method as defined in claim3, wherein the first threshold value depends on the location of thefirst sensor.
 5. A method as defined in claim 3, further comprising:calculating a difference based on the third vibration data and thesecond vibration data; and determining the condition of the processcontrol device when the difference exceeds a second threshold value. 6.A method comprising: collecting first vibration data from a first sensoroperatively coupled to a process control device and second vibrationdata from a second sensor operatively coupled to a pipe, wherein thepipe is coupled to the process control device; calculating, by executingan instruction with a vibration monitoring circuit, a ratio based on thefirst vibration data and the second vibration data; collecting usageinformation associated with the process control device, the usageinformation indicative of a remaining portion of useful life associatedwith the process control device; adjusting, by executing an instructionwith the vibration monitoring circuit, a threshold value based on theusage information, the adjusted threshold value reflective of theremaining portion of useful life associated with the process controldevice; and determining, by executing an instruction with the vibrationmonitoring circuit, a condition of the process control device if theratio is greater than the adjusted threshold value.
 7. A method asdefined in claim 6, wherein the first and second vibration data includeacceleration data, velocity data, displacement data or frequency data.8. A method as defined in claim 6, wherein the threshold value dependson the location of the first sensor.
 9. A method comprising: collectingvibration data from a first sensor operatively coupled to a processcontrol device; accessing a predetermined diagnostic vibration patternassociated with the process control device; collecting usage informationassociated with the process control device, the usage informationindicative of a remaining portion of useful life associated with theprocess control device; adjusting, by executing an instruction with avibration monitoring circuit, the predetermined diagnostic vibrationpattern based on the usage information, the adjusted diagnosticvibration pattern reflective of the remaining portion of useful lifeassociated with the process control device; comparing, by executing aninstruction with the vibration monitoring circuit, the vibration data tothe adjusted diagnostic vibration pattern; and determining, by executingan instruction with the vibration monitoring circuit, a condition of theprocess control device based on the comparison.
 10. A method as definedin claim 9, wherein the vibration data includes known vibration dataranges.
 11. A method as defined in claim 9, wherein the vibration dataincludes acceleration data, velocity data, displacement data orfrequency data.
 12. A method as defined in claim 9, further comprising:collecting second vibration data from a second sensor operativelycoupled to a pipe, the pipe coupled to the process control device;calculating a ratio between the vibration data associated with theprocess control device and the second vibration data; and determining acondition of the process control device when the ratio exceeds athreshold value.
 13. A method as defined in claim 12, wherein thethreshold value depends on the location of the first sensor.
 14. Amethod as defined in claim 9, wherein the vibration data includes afrequency range.
 15. A method as defined in claim 14, wherein thefrequency range indicates a control instability of the process controldevice.
 16. A method as defined in claim 15, wherein the frequency rangeincludes 1 Hertz to 10 Hertz.
 17. A method as defined in claim 14,wherein the frequency range indicates a condition with a process flowassociated with the process control device.
 18. A method as defined inclaim 17, wherein the frequency range includes 10 Hertz to 100 Hertz.19. A method as defined in claim 14, wherein the frequency rangeindicates a condition associated with a valve trim of the processcontrol device.
 20. A method as defined in claim 19, wherein thefrequency range includes frequencies greater than 100 Hertz.
 21. Amethod comprising: collecting usage information associated with aprocess control device, the usage information indicative of a remainingportion of useful life associated with the process control device;adjusting, by executing an instruction with a vibration monitoringcircuit, a known threshold range associated with the process controldevice based on the usage information, the adjusted known thresholdrange reflective of the remaining portion of useful life associated withthe process control device; collecting first vibration data from a firstsensor operatively coupled to the process control device; identifying,by executing an instruction with the vibration monitoring circuit, acharacteristic of the process control device from the first vibrationdata; determining, by executing an instruction with the vibrationmonitoring circuit, if the characteristic is within the adjusted knownthreshold range; and if the characteristic is within the adjusted knownthreshold range, determining, by executing an instruction with thevibration monitoring circuit, a condition of the process control device.22. A method as defined in claim 21, further comprising: collectingsecond vibration data from a second sensor operatively coupled to apipe, the pipe coupled to the process control device; calculating aratio based on the first vibration data and the second vibration data;and determining the condition of the process control device when theratio exceeds a threshold value.
 23. A method as defined in claim 1,wherein the usage information includes operational cycles information ordistance traveled.